With regard to road tanker design, primary features are those which are preventative. Primary safety features include those design features which contribute to the stability of a tanker load. For example, the lower the center of gravity, the greater the lateral acceleration that can be tolerated before a roll-over. Secondary safety features are those which influence the ability of a tanker to resist fracture, rupture or puncture in the case of a roll-over or accident. These primary and secondary features must be balanced against efficiency, load carrying ability and cost.
Most tankers are circular, eliptical, oval or similarly shaped because these shapes are regarded as having good structure integrity for carrying liquids. However, these shapes have a higher centre of gravity compared to tanks having a more rectangular shape. Further, rounded types of tanks tend to keep rolling in a roll-over, whereupon a large portion of the shell is subject to impact and wear.
There exists the need for a road tanker of a more rectangular shape and low centre of gravity but which satisfies the mechanical, economic and regulatory constraints which are present in the industry.